1. Field of the Invention
THIS INVENTION relates to a document authentication method and apparatus.
The invention is particularly suitable for, but not limited to, validation of financial instruments, including cash (ie., bank notes), personal cheques, traveller's cheques, credit cards, debit cards and the like.
The invention is also particularly suitable for, but not limited to, the validation of legal instruments such as letters, agreements, licences, bills, and copies (eg., photocopies) thereof.
2. Prior Art
The counterfeiting of documents, particularly currency, has been a major problem for the authorities for many years. Money issuing authorities (eg., Reserve Banks or Mints) have adopted many different methods in an attempt to overcome or minimise counterfeiting of currency and other financial documents, and examples have included features or indicia such as watermarks and holograms. Examples of papers discussing such matters include (1) “Spacial Logic Algorithms Using Basic Morphological, Anologic CNN Operations” (Zarande et al) in “The Proceedings of the 1994 Third IEEE International Workshop on Cellular Neural Networks and their Applications”, Rome, Italy, published in the “International Journal of Circuit Theory and Applications” v 24 n 3 May–June 1996, pages 283–300; (2) “Development of Embossed Holograms” (Haines) in “Proceedings of SPIE—The International Society for Optical Engineering”, v 2652, 1996, Society of Photo-Optical Instrumentation Engineers, Bellingham, Wash., United States of America, pages 45–52; (3) “Performance of Diffraction Grating on a Banknote—The Experience with the Australian Commemorative Note” (Hardwick) in “Proceedings of SPIE—The International Society for Optical Engineering”, v 1210, published by The International Society for Optical Engineering, Bellingham, Wash., United States of America, pages 20–26; (4) “Optically Variable Devices for use on Bank Notes” (Rolfe) in “Proceedings of SPIE—The International Society for Optical Engineering” v 1210, published by the International Society for Optical Engineering, Bellingham, Wash., United States of America, pages 14–19; (5) “Evaluation of Security Features for new U.S. Currency” (Church et al) in “Proceedings of SPIE—The International Society for Optical Engineering”, v 2659, 1996, Society of Photo Optical Instrumentation Engineers, Bellingham, Wash., United States of America, pages 28–36.
Whilst such authentication features or indicia can be placed in bank notes, currency or other financial or legal documents, there is a need for financial or legal instruments bearing such indicia, to be rapidly and accurately-identified and authenticated.